On-machine measurement method of geometric errors of three-axis CNC machine tools based on pose transformation of characteristic samples

Abstract

A kind of three-axis numerical control machine tool geometric error on-machine measurement method based on feature sample pose transformation, by designing feature sample and planning feature point group, after accurate calibration, feature sample is placed on machine tool worktable to carry out on-machine measurement, by measuring the combination of feature points of feature sample in different poses on machine tool, multiple identification models for different types of geometric error items are established, and all 21 geometric errors of three-axis machine tool are quickly identified.The present application can quickly measure geometric error without precise measuring equipment or instrument, and the numerical control program for measuring feature points of sample can be used repeatedly for a long time after being compiled, which greatly improves the measurement efficiency of geometric error, and can be used for quickly and efficiently detecting periodicity of machine tool and precision calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of three-axis numerical control machine tools, and particularly relates to a three-axis numerical control machine tool geometric error on-machine measurement method based on feature sample pose transformation. BACKGROUND

[0002] There are 21 geometric errors in a three-axis machine tool. Currently, laser interferometers are usually used to directly or indirectly measure the geometric errors. The device installation and debugging are time-consuming and laborious, and require a certain level of professional measurement operation, so it is difficult to realize automatic measurement, and the overall measurement efficiency is low. The prior art can only identify nine linear motion errors of the XYZ axis, and the error compensation accuracy of the machine tool motion needs to be improved. SUMMARY

[0003] The present application proposes a three-axis numerical control machine tool geometric error on-machine measurement method based on feature sample pose transformation to solve the above problems in the prior art. The geometric error can be quickly measured without precise measuring devices or instruments. Once the numerical control program for measuring the feature points of the sample is compiled, it can be repeatedly used for a long time, which greatly improves the measurement efficiency of the geometric error, and can identify the angle error of the linear axis of the three-axis numerical control machine tool, including the pitch, yaw and roll errors in the XYZ three directions, and the perpendicularity error between the XYZ axes, which greatly improves the compensation accuracy of the machine tool spatial error.

[0004] The present application is implemented through the following technical solutions:

[0005] The present application relates to a three-axis numerical control machine tool geometric error on-machine measurement method based on feature sample pose transformation. The feature sample is designed and the feature point group is planned. After accurate calibration, the feature sample is placed on the machine tool workbench for on-machine measurement. The feature points of the feature sample in different poses on the machine tool are measured, multiple identification models for different types of geometric error items are established, and all 21 geometric errors of the three-axis machine tool are quickly identified.

[0006] The feature sample is a kind of metal product with multiple steps, and the steps have at least one rising direction.

[0007] The feature point group is a point group to be measured for identifying the 21 geometric errors, and specifically includes:

[0008] ① Positioning error identification point group, i.e. combination of points on different step surfaces of the feature sample;

[0009] ② Straightness error identification point group, i.e. equidistant feature points distributed on a straight line on the same step surface of the feature sample;

[0010] ③ Angle error point group, i.e. the combination of feature points distributed on multiple straight lines on multiple stepped surfaces of the feature sample;

[0011] ④ Perpendicularity error point group, i.e. the combination of feature points distributed on two straight lines of two stepped surfaces.

[0012] The in-machine measurement refers to connecting the measuring head directly with the spindle of the three-axis numerical control machine tool, moving the measuring head together with the spindle of the three-axis numerical control machine tool, and measuring the part directly on the machine tool workbench.

[0013] The 21 geometric errors include 1 positioning error, 2 straightness errors, 3 angle errors of each translational axis, and perpendicularity errors between three translational axes, for example, for the x-axis, 1 positioning error , 2 straightness errors and , 3 angle errors: pitch angle error , yaw angle error , roll angle error , and the perpendicularity error between the x-axis and the y-axis .

[0014] The combination of different poses refers to that different poses of the sample on the machine tool workbench correspond to different types of geometric errors according to the zero position of the machine tool workbench coordinate system, i.e. the identification of 21 geometric errors corresponding to the poses of the 7 feature samples on the workbench, specifically including: pos1 corresponding to the x-axis positioning error and the z-axis positioning error , pos2 corresponding to the x-axis straightness error in the z direction , the x-axis straightness error in the y direction , the perpendicularity error between the x-axis and the y-axis , the x-axis yaw error , the z-axis pitch error and the z-axis yaw error , pos3 corresponding to the x-axis roll error and the y-axis positioning error , pos4 corresponding to the y-axis straightness error in the z direction , the y-axis straightness error in the x direction and the y-axis yaw error , pos5 corresponding to the y-axis roll error , pos6 corresponding to the x-axis pitch error , the z-axis straightness error in the x direction , the perpendicularity error between the x-axis and the z-axis , the z-axis straightness error in the y direction and the z-axis roll error pos7 corresponds to the y-axis pitch error and the perpendicularity error of the y-axis and the z-axis , wherein: pos1, pos2, pos3, pos4, pos5, pos6 and pos7 are respectively the first to the seventh feature piece placed on the workbench position.

[0015] The identification model comprises: a positioning error identification model, a straightness error identification model, a pitch angle error identification model, a yaw angle error identification model, a roll angle error identification model and a perpendicularity error identification model.

[0016] The positioning error identification model specifically refers to: the x-axis positioning error , the y-axis positioning error , and the z-axis positioning error , wherein: , , is the distance value of the feature point obtained by measuring the step surface and the reference step surface in the x, y and z directions on the feature piece, , , is the calibration value of the distance between the step surface and the reference step surface in the x, y and z directions, , , is , , corresponding positioning error at the coordinate position.

[0017] The straightness error identification model specifically refers to: the x-axis in the y direction and the z direction respectively , , the y-axis in the x direction and the z direction respectively , , and the z-axis in the x direction and the y direction respectively , , wherein: is the distance between the feature points and the reference straight line in the y direction when the feature points on a straight line are fitted as the x-direction reference straight line, and the rest are similar; is the calibration value of the distance between the feature points and the reference straight line in the y direction when the feature points are fitted as the x-direction reference straight line, and the rest are similar; is corresponding straightness error in the y direction at the coordinate position, and the rest are similar.

[0018] The pitch angle error identification model specifically refers to: the x-axis pitch error , the y-axis pitch error , and the z-axis pitch error wherein: the characteristic points linearly distributed on the multiple step surfaces are fitted to multiple straight lines perpendicular to the x direction, the straight line corresponding to the coordinate zero point is the reference straight line, and the included angle of the other straight lines with the reference straight line changing around the y axis is , and the rest are similar; the same characteristic points are fitted to multiple straight lines perpendicular to the x direction, and the included angle of the other straight lines with the reference straight line rotating around the y axis is , and the rest are similar; , , , or corresponding to the pitch angle error when the coordinate position is

[0019] The yaw angle error identification model, specifically refers to: the x-axis yaw error , the y-axis yaw error , and the z-axis yaw error wherein: the characteristic points linearly distributed on the multiple step surfaces are fitted to multiple straight lines perpendicular to the x direction, the straight line corresponding to the coordinate zero point is the reference straight line, and the included angle of the other straight lines with the reference straight line changing around the z axis is , and the rest are similar; the same characteristic points are fitted to multiple straight lines perpendicular to the x direction, and the included angle of the other straight lines with the reference straight line rotating around the z axis is , and the rest are similar; , , , or corresponding to the yaw angle error when the coordinate position is

[0020] The roll angle error identification model, specifically refers to: the x-axis roll error , the y-axis roll error , and the z-axis roll error wherein: is the difference between the in-machine measurement value and the calibration value of the point in the z direction at the coordinate position , , and the rest are similar; , , , or corresponding to the roll angle error when the coordinate position is

[0021] ​​​The perpendicularity error identification model, in particular refers to: Wherein: , , , is the slope of the straight line fitted by the feature points in the x-axis and y-axis directions, is the calibrated value of the included angle of the straight line fitted by the same feature points in the x-axis and y-axis directions, is the perpendicularity error between the x-axis and the y-axis. And The perpendicularity error identification method is similar .

[0022] Technical effects

[0023] Compared with the existing three-axis machine tool geometric error measurement method, the present application considers adopting the feature sample after accurate calibration, planning multiple groups of feature points on different step surfaces of the sample, measuring the feature points in different combinations in different directions and lengths on the machine tool workbench, establishing an identification model for all 21 geometric errors of the three-axis machine tool, and then quickly and efficiently measuring the geometric errors. Compared with the existing method, this method does not require high-precision measuring equipment and instruments, thereby saving the time for installing and debugging the instruments, and the numerical control program for measuring the feature points of the sample can be repeatedly used for a long time after being compiled. Compared with identifying part of the geometric errors to compensate for the position accuracy of the machine tool, the present application can quickly identify all 21 geometric errors of the three-axis machine tool while greatly improving the accuracy of the space error compensation of the machine tool. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the flowchart of the present application;

[0025] Figure 2 is a schematic diagram of the geometric errors contained in the measured machine tool in the embodiment;

[0026] Figure 3 is a schematic diagram of the feature sample in the embodiment;

[0027] Figure 4 is a schematic diagram of different placement poses of the feature sample on the machine tool workbench in the embodiment;

[0028] Figures 5-11 is a schematic diagram of the feature points required to be measured on the machine in the embodiment corresponding to the geometric error items of pos1-pos7 poses;

[0029] Figure 12 is a schematic diagram of the pitch angle error identification model in the embodiment;

[0030] Figure 13 is a schematic diagram of the roll angle error identification model in the embodiment;

[0031] Figure 14 Roll angle error identification model schematic diagram for the embodiment;

[0032] Figure 15 Perpendicularity error identification model schematic diagram for the embodiment;

[0033] Figures 16-18 Respectively, the x, y, z axis geometric error in-machine measurement result schematic diagram for the embodiment;

[0034] Figure 19 For the embodiment, the effect diagram after machine tool geometric error identification and machine tool error compensation;

[0035] Figure 20 For the effect diagram after error measurement and compensation of the embodiment;

[0036] Figure 21 For the on-site diagram of the embodiment. DETAILED DESCRIPTION

[0037] As Figure 1 shown, the embodiment relates to a three-axis NC machine tool geometric error in-machine measurement method based on feature sample pose transformation, comprising: designing multiple groups of feature points corresponding to different geometric error items on the planned surface of the feature sample, accurately calibrating the feature points of the sample; compiling a numerical control in-machine measurement program according to the planned feature points; transforming the different poses of the feature sample on the machine tool workbench to execute the measurement program, and obtaining feature point coordinate data; establishing an identification model for different geometric error items to obtain all 21 items of geometric error of the three-axis machine tool, specifically comprising:

[0038] Firstly, multiple groups of feature points corresponding to different geometric error items on the planned surface of the feature sample are designed, different groups of feature points correspond to 21 items of geometric error, and the feature points of the sample are accurately calibrated.

[0039] As Figure 2 shown, the 21 items of geometric error are error indicators reflecting the geometric motion accuracy of the three translational axes of the three-axis machine tool, specifically comprising: 1 item of positioning error, 2 items of straightness error, and 3 items of angle error exist for each translational axis, for example, for the y-axis, 1 item of positioning error , 2 items of straightness error and , and 3 items of angle error: pitch angle error , yaw angle error , and roll angle error ; perpendicularity error exists between the three translational axes, for example, the perpendicularity error between the x-axis and the y-axis .

[0040] As Figure 3As shown, the feature sample is a kind of metal product with multiple levels of steps, and the rising direction of the steps is not only one.

[0041] The multiple groups of feature points correspond to the point groups to be measured in the identification of 21 geometric error items. Specifically, the point group required for positioning error identification is the combination of points on different step surfaces of the feature sample; the point group required for straightness error identification is the equidistance feature points distributed on a straight line on the same step surface of the feature sample; the point group required for angle error is the combination of feature points distributed on multiple straight lines on multiple step surfaces of the feature sample; and the point group required for perpendicularity error is the combination of feature points distributed on two straight lines on two step surfaces. For example, Figure 6 As shown, the linear geometric error and the angle geometric error correspond to different geometric error items.

[0042] Second step, according to the planned feature points to compile numerical control program for in-machine measurement;

[0043] The in-machine measurement is to directly connect the measuring head with the main shaft of the machine tool, and then the motion control system of the machine tool drives the main shaft and the measuring head to move together to measure the part directly on the machine tool workbench.

[0044] Third step, transform the different poses of the feature sample on the machine tool workbench to execute the measurement program and obtain the feature point coordinate data;

[0045] As shown, the different poses of the feature sample on the machine tool workbench in the embodiment are shown in the schematic diagram; as shown, Figure 4 The different poses in the embodiment correspond to different geometric error items, which correspond to pos1 to pos7 respectively. Figures 5 to 11

[0046] The different poses refer to that according to the zero point position of the machine tool workbench coordinate system, the different poses of the sample on the machine tool workbench correspond to different types of geometric errors, which specifically include: 7 poses correspond to the identification of 21 geometric errors, pos1 corresponds to x-axis positioning error and z-axis positioning error ; pos2 corresponds to x-axis straightness error in z direction , x-axis straightness error in y direction , x-axis and y-axis perpendicularity error , x-axis yaw error , z-axis pitch error and z-axis yaw error ; pos3 corresponds to x-axis roll error and y-axis positioning error ; pos4 corresponds to y-axis straightness error in z direction , y-axis straightness error in x direction and y-axis yaw error​ ; pos5 corresponds to the y-axis roll error ; pos6 corresponds to the x-axis pitch error , the straightness error of the z-axis in the x direction , the perpendicularity error of the x-axis and the z-axis , the straightness error of the z-axis in the y direction and the z-axis roll error ; pos7 corresponds to the y-axis pitch error and the perpendicularity error of the y-axis and the z-axis , wherein: pos1, pos2, pos3, pos4, pos5, pos6 and pos7 are respectively the feature sample placed on the workbench in position 1, position 2, position 3, position 4, position 5, position 6 and position 7.

[0047] The fourth step is to establish an identification model for different geometric error items, and obtain all 21 geometric error items of the three-axis machine tool.

[0048] The identification model of different geometric error items includes positioning error identification model, straightness error identification model, pitch angle error identification model, yaw angle error identification model, roll angle error identification model and perpendicularity error identification model.

[0049] The positioning error identification model includes x-axis positioning error , y-axis positioning error , z-axis positioning error , wherein: , , is the distance value obtained by measuring the feature point on the step surface and the reference step surface in the x, y and z directions of the feature sample, , , is the calibration value of the distance between the step surface and the reference step surface in the x, y and z directions, 、 , is 、 , the corresponding positioning error of the coordinate position.

[0050] The straightness error identification model includes 、 , the y-axis in the x direction and the z direction respectively 、 , the z-axis in the x direction and the y direction respectively 、 , wherein: For the same feature points, the fitting is a straight line in the x direction, and the distance between the feature points and the reference straight line in the y direction is calibrated, and the rest is similar. For the same feature points, the fitting is a reference straight line in the x direction, and the distance between the feature points and the reference straight line in the y direction is calibrated, and the rest is similar. For The straightness error in the y direction corresponding to the coordinate position, and the rest is similar.

[0051] As Figure 12 shown, the x-axis pitch angle error identification model, the x-axis pitch error , the y-axis pitch error , the z-axis pitch error , wherein: a plurality of linearly distributed feature points on a plurality of step surfaces are fitted to a plurality of straight lines perpendicular to the x direction, and the straight line corresponding to the coordinate zero point is the reference straight line, and the included angle between the other straight lines and the reference straight line around the y axis is , and the rest is similar; the same feature points are fitted to a plurality of straight lines perpendicular to the x direction, and the included angle between the other straight lines and the reference straight line around the y axis is calibrated , and the rest is similar; , , For , or the pitch angle error corresponding to the coordinate position.

[0052] As Figure 13 shown, the x-axis yaw angle error identification model, the x-axis yaw error , the y-axis yaw error , the z-axis yaw error , wherein: a plurality of linearly distributed feature points on a plurality of step surfaces are fitted to a plurality of straight lines perpendicular to the x direction, and the straight line corresponding to the coordinate zero point is the reference straight line, and the included angle between the other straight lines and the reference straight line around the z axis is , and the rest is similar; the same feature points are fitted to a plurality of straight lines perpendicular to the x direction, and the included angle between the other straight lines and the reference straight line around the z axis is calibrated , and the rest is similar; , , For , or the yaw angle error corresponding to the coordinate position. The yaw angle error identification model principle is similar to the pitch angle error identification model principle, but in essence the feature points required by the former are different from the feature points required by the latter. The direction of the fitted straight line and the direction of the rotation axis are also different.

[0053] AsFigure 14 As shown, the x-axis roll angle error identification model, x-axis roll error , y-axis rolling error , z-axis roll error ,in: For 、 At the coordinate position, the difference between the measured value and the calibration value of the point in the z direction, and the rest are similar; , , for 、 or The roll angle error corresponding to the coordinate position.

[0054] like Figure 16 17a-f, 17a-f, and 18a-f respectively show the six geometric errors of the x, y, and z axes identified in this embodiment.

[0055] like Figure 15 As shown, the x-axis and y-axis verticality error identification model, ,in: , , , is the slope of the straight line fitting the feature points in the x-axis and y-axis directions, is the calibration value of the angle between the straight lines fitted to the same feature points in the x-axis and y-axis directions, is the perpendicularity error between the x-axis and the y-axis. and The verticality error identification method is similar , specifically, the identification results obtained are: , , .

[0056] Through specific actual experiments, it was found that after the machine tool has been running for a period of time, the characteristic sample of the present invention can be placed on the machine tool workbench, and the CNC program that does not need to be modified once it is compiled can be run in conjunction with the on-machine measuring device to measure the machine tool's geometric errors. In a relatively short time, all 21 geometric errors of the three-axis machine tool can be obtained, preparing for the machine tool's precision compensation.

[0057] like Figure 19 The figure shows an on-site picture of on-machine measurement of a characteristic sample in the embodiment.

[0058] Compared with the existing technology, this method can quickly obtain all 21 geometric errors of the three-axis machine tool. Compared with the method that can only identify some geometric error items, the present invention can improve the accuracy of machine tool error compensation, thereby improving the machining accuracy of the machine tool and ensuring the consistency of part machining quality.

[0059] As Figure 20 shown, the dotted part represents the result of measuring the linear geometric error of the straight line axis of the measured part and compensating the in-machine length error of the machine tool, and the solid part represents the result of measuring the whole geometric error of the machine tool including the angle error and compensating the in-machine length error of the machine tool, both of which are measured on the X, Y and 4 individual diagonal lines of the machine tool. After the measurement and compensation by the method of the present application, the length measurement error of the machine tool is greatly reduced, i.e. the position accuracy is greatly improved, and the accuracy of the compensation is greatly improved.

[0060] As Figure 21 shown, the dotted part represents the result of measuring the linear geometric error of the straight line axis of the measured part and compensating the in-machine length error of the machine tool, and the solid part represents the result of measuring the whole geometric error of the machine tool including the angle error and compensating the in-machine length error of the machine tool, both of which are measured on the X, Y and 4 individual diagonal lines of the machine tool. After the measurement and compensation by the method of the present application, the length measurement error of the machine tool is greatly reduced, i.e. the position accuracy is greatly improved, and the accuracy of the compensation is greatly improved.

[0061] The above specific embodiments can be adjusted in different ways by those skilled in the art without departing from the principles and purposes of the present application, the protection scope of the present application is subject to the claims and is not limited by the above specific embodiments, and each implementation scheme within the scope is subject to the present application.

Claims

1. A method for measuring geometric errors of three-axis CNC machine tools on-machine based on feature sample pose transformation, characterized in that: By designing characteristic samples and planning characteristic point groups, the characteristic samples are placed on the machine tool workbench after precise calibration for on-machine measurement. By measuring the characteristic points of the characteristic samples at different positions on the machine tool, multiple identification models for different types of geometric error terms are established, and all 21 geometric errors of the three-axis machine tool can be quickly identified. The characteristic sample is a type of metal product with multiple steps and the steps have at least one ascending direction; The feature point group is a point group to be measured when identifying 21 geometric errors, specifically including: ① Positioning error identification point group, that is, the combination of points on different step surfaces on the characteristic sample; ②Straightness error identification point group, that is, the equidistant characteristic points distributed on a straight line on the same step surface of the characteristic sample; ③ Angle error point group, that is, the combination of characteristic points distributed on multiple straight lines on multiple step surfaces of the characteristic sample; ④ Verticality error point group, that is, the combination of characteristic points distributed on two straight lines on two step surfaces; The identification models include: positioning error identification model, straightness error identification model, pitch angle error identification model, yaw angle error identification model, roll angle error identification model and verticality error identification model; The combination of different postures means that according to the zero position of the machine tool table coordinate system, different postures of the feature sample on the machine tool table correspond to different types of geometric errors, that is, the 7 feature samples placed on the table correspond to the identification of 21 geometric errors, specifically including: pos1 corresponds to the x-axis positioning error and z-axis positioning error , pos2 corresponds to the straightness error of the x-axis in the z-direction , straightness error of x-axis in y direction , perpendicularity error between x-axis and y-axis , x-axis runout error , z-axis pitch error and z-axis yaw error , pos3 corresponds to the x-axis rolling error and y-axis positioning error , pos4 corresponds to the straightness error of the y-axis in the z direction , straightness error of y-axis in x-direction and y-axis yaw error , pos5 corresponds to the y-axis rolling error , pos6 corresponds to the x-axis pitch error , straightness error of z-axis in x-direction , perpendicularity error between x-axis and z-axis , straightness error of z-axis in y direction and z-axis roll error , pos7 corresponds to the y-axis pitch error and the perpendicularity error between the y-axis and the z-axis , where: pos1, pos2, pos3, pos4, pos5, pos6 and pos7 are the positions of the first to seventh feature samples placed on the workbench respectively.

2. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1 is characterized in that: The on-machine measurement refers to: directly connecting the probe to the main shaft of the three-axis CNC machine tool, and measuring the part directly on the machine tool workbench through the movement of the main shaft of the three-axis CNC machine tool and the probe.

3. The on-machine geometric error measurement method for a three-axis CNC machine tool based on characteristic sample pose transformation according to claim 1 is characterized in that: The total of 21 geometric errors include: 1 positioning error, 2 straightness errors, 3 angular errors, and perpendicularity errors between the three translation axes for each translation axis; for the x-axis, there is 1 positioning error , 2 straightness errors and , 3 angle errors: pitch angle error , yaw angle error , roll angle error And the perpendicularity error between the x-axis and the y-axis .

4. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1 is characterized in that: The positioning error identification model specifically refers to: x-axis positioning error , y-axis positioning error , z-axis positioning error ,in: , , The distance between the step surface in the x, y, and z directions on the characteristic sample and the reference step surface at the characteristic point measured by the machine is: , , is the calibration value of the distance between the step surface and the reference step surface in the x, y, and z directions, 、 , They are 、 , The corresponding positioning error when the coordinate position is determined.

5. The on-machine geometric error measurement method for a three-axis CNC machine tool based on characteristic sample pose transformation according to claim 1 is characterized in that: The straightness error identification model specifically refers to: the x-axis in the y direction and the z direction are respectively 、 , the y-axis is in the x-direction and the z-direction respectively 、 , the z-axis is in the x-direction and y-direction respectively 、 ,in: The feature points distributed on a straight line during machine measurement are fitted into the x-direction reference line. The distance between the feature points and the reference line in the y-direction is calculated, and the rest are similar. Fit the same feature point to a reference line in the x-direction, and calibrate the distance between the feature point and the reference line in the y-direction. The rest are similar. for The straightness error in the y direction corresponds to the coordinate position, and the rest is similar.

6. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1 is characterized in that: The pitch angle error identification model specifically refers to: x-axis pitch error , y-axis pitch error , z-axis pitch error , where: the characteristic points linearly distributed on the multiple step surfaces measured by the machine are fitted with multiple straight lines perpendicular to the x-direction. The straight line corresponding to the coordinate zero point is the reference straight line, and the angle between the other straight lines and the reference straight line around the y-axis is , the rest are similar; the same feature points are fitted into multiple straight lines perpendicular to the x-direction, and the calibration value of the angle between the other straight lines and the reference straight line rotated around the y-axis is , the rest is similar; , , They are 、 、 The pitch angle error corresponding to the coordinate position.

7. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1 is characterized in that: The yaw angle error identification model specifically refers to: x-axis yaw error , y-axis runout error , z-axis runout error , where: the linearly distributed feature points on the multiple step surfaces measured by the machine are fitted into multiple straight lines perpendicular to the x-direction, the straight line corresponding to the coordinate zero point is the reference straight line, and the angle between the other straight lines and the reference straight line around the z-axis is , the rest are similar; the same feature points are fitted to multiple straight lines perpendicular to the x-direction, and the calibration value of the angle between the other straight lines and the reference straight line around the z-axis is , the rest is similar; , , They are 、 、 The yaw angle error corresponding to the coordinate position, the yaw angle error identification model principle is similar to the pitch angle error identification model principle, but in essence the feature points required by the former and the latter are different feature point combinations, and the direction of the fitting line and the direction of the rotation axis are also different.

8. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1 is characterized in that: The roll angle error identification model specifically refers to: x-axis roll error , y-axis rolling error , z-axis roll error ,in: For 、 At the coordinate position, the difference between the measured value and the calibration value of the feature point in the z direction, and the rest are similar; , , They are 、 、 The roll angle error corresponding to the coordinate position.

9. The method for measuring geometric errors of three-axis CNC machine tools based on characteristic sample pose transformation according to claim 1, characterized in that: The verticality error identification model specifically refers to: ,in: , , , is the slope of the straight line fitting the feature points in the x-axis and y-axis directions, is the calibration value of the angle between the straight lines fitted to the same feature points in the x-axis and y-axis directions, is the perpendicularity error between the x-axis and the y-axis, and The verticality error identification method is similar .

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